Electrooptical device for discriminating a predetermined pattern from others by detecting preselected color changes identifying the pattern

ABSTRACT

A pattern to be discriminated from other patterns comprises a frame of a predetermined size and color on a predetermined background color. The device comprises a first unit for producing electric signals responsive to the color change from the background color to the pattern color and the reversed color change and a second unit, responsive to these electric siganls, for measuring the distance between the boundaries across which the color change takes place.

United States Patent 1 1 Yoshimura et al.

ELECTROOPTICAL DEVICE FOR DISCRIMINATING A PREDETERMINED PATTERN FROMOTHERS BY DETECTING PRESELECTED COLOR CHANGES IDENTIFYING TI-IE PATTERNInventors: Shoichiro Yoshimura; Rinzou Ebukuro; Tomoyuki lsono, all ofMinato-ku, Tokyo, Japan Nippon Electric Company, Limited, Tokyo, JapanFiled: Dec. 7, 1971 Appl. No.: 205,666

Assignee:

Foreign Application Priority Data Dec. 9, 1970 Japan ..L 45/108525 US.Cl. 340/1463 B, 235/6111 E, 209/1 11.6, 356/178 1111. c1. G06r 7 00, 001j 3 34 Field 61 Search 340/1463 B, 146.3 2, 340/1463 K; 235/61.11 E,61.11 F; 209/1ll.6, 111.5; 101/181, 184; 356/178 111970 Mori et a1.209/lll.6

Primary Examiner-Thomas A. Robinson Att0rney- Richard C. Sughrue, J.Frank Osha et al.

[5 7 ABSTRACT A pattern to be discriminated from other patternscomprises a frame of a predetermined size and color on a predeterminedbackground color. The device comprises a first unit for producingelectric signals responsive to the color change from the backgroundcolor to the pattern color and the reversed color change and a secondunit, responsive to these electric siganls, for measuring thedistance'between the boundaries across which the color change takesplace.

7 Claims, 11 Drawing Figures PHOTO A TUBE NORM A 5 PHOTO TUBE NORM0010111 1 L 013011 001011 L DISCR.

c0100 GL DETECT FRAME PAIENTEU JUL 1 mm sum 1 or 3 PATENTE JUL 1 0:915

SHEEI 2 0F 1 ELECTROOPTICAL DEVICE FOR DISCRIMINATING A PREDETERMINEDPATTERN FROM OTHERS BY DETECTING PRESELECTED COLOR CHANGES IDENTIFYINGTHE PATTERN BACKGROUND OF THE INVENTION This invention relates to anelectrooptical device for discriminating a predetermined color patternfrom other patterns by detecting color variations in the patterns. Thedevice is useful in distinguishing between various postage stamps, banknotes, securities, and other such papers and in checking the aligning orregister marks in multicolor printing.

Electrooptical recognition of a colored pattern has been applied tomulticolor printing for checking the aligning marks. The recognitiontechnique is based on the color contrast. More particularly, light froman incandescent lamp is focussed onto a spot where the aligning marksare caused to pass. The rays reflected from the paper on which themulticolor figure is printed is directed to a phototube or moregenerally to a photoelectric transducer. Inasmush as the .output .of thephotoelectric transducer, which is responsive to the rays reflected fromthe colored portion, decreases in compliance with the spectralsensitivity, a decrease in the output below a predetermined level isunderstood to be recognition of an aligning mark. lt is thus possible todetect the inadvertent omission of a color in the multicolor printing bythe number of the recognized aligning marks without regard torecognition of the individual colors and to check the undesirable shearor out of register in printing by electrically measuring the distancesbetween the aligning marks. This method is defective in tliat it isimpossible to distinguish the aligning marks from an indent on thesurface of the paper or a stain thereon of a color other than thepredetermined colors.

The color contrast method may be used in a process of identifyingpredetermined color patterns on bank notes, securities, certificatestamps, and the like but is not immune from the above-mentioned defectwhich is inherent to the principles of this method.

The aligning marks are printed on a sheet of white paper. Besides theirlengths, the characteristic features of aligning marks may include thefollowing three items or attributes:

l. The color varies in the order of white color white;

2. The first white portion and the second white portion are spaced apartby the definite width; and

3. the color is predetermined.

The concept of these characteristic features is applicable to banknotes, securities, certificate stamps, and the like. lt is, however, tobe noted that contrary to the aligning marks which are color patterns ofsubstantially uniform depth, it is difficult to establish the threeitems in the case of bank notes, securities, certificate stamps, and thelike in that they have complicated'patterns in various colors. If theselatter mentioned papers are provided with a frame of a predeterminedcolor, recognition thereof would be possible by means of the same itemsas the aligning marks. Even if provision of a color frame is impossible,recognition might be possible if attention could be directed toaparticular color distribution in the pattern and to the similar itemsas those for the aligning marks. In this latter case, an item The orderof a color A a color B a color C should be substituted for the item lThe order of white color white.

Among certificate stamps having the color frames are postage stamps. lnautomatic mail handling systems, the color frames are detected to aid inproperly orienting the letters and postcards in the system, to aid inchecking the postage, and placing postmarks across the stamps.

It is possible to discriminate postage stamps which are not subjected tospecial treatment but which are provided with patterns having framesprinted in predetermined clearly distinguishable colors. The recognitionis based only on the color and the dimensions of the frame printed onthe postage stamps. Restrictions on the postage stamp design are suchthat the designed pattern should have a substantially rectangular frameof a clearly distinguishable and uniform color, having a predeterminedlength,'width, and minimum predetermined thickness of, for example, 0.5mm. Except for such restrictions, the color and the design of thepostage stamps are free and subject to no further restrictions. However,it often occurs that the face of the mail bearing the stamp also bearsan address, a message, and some printed letters and ornaments whichhappen to be quite similar to the predetermined color and dimensions ofa postage stamp thus resulting in a possible misrecognition. With aconventional poastage stamp recognition device, high technical skill andacomplicated control circuit are necessary to discriminate the postagestamps from various noises, such as the letters and the ornaments. Oneof such conventional recognition devices is described in Proceedings ofthe Institution of Mechanical Engineers, Volume 184 (1969-), Part 3H,British Postal Engineering," Paper 17 Automatic Letter Facing.

SUMMARY OF THE INVENTION .It is, therefore, an object of the presentinvention to provide an electrooptical device for discriminating apredetermined color pattern from other patterns, th device beinginexpensive and yet reliable.

It is another object to provide a device of the type which isinsensitive toirregularities in the surface hear ing the pattern to bediscriminated.

It is still another object to provide a device of the type which isinsensitive to noise signals caused by letters, ornaments, or otherpatterns. These patterns wouldresult in a misrecognition if conventionaldevices were used It should be remembered that a pattern to berecognized by a device according to the instant invention is providedwith a frame of predetermined dimensions and'having at least onepredetermined pattern color on a background of at least onepredetermined background color, the background color generally beingselected from the colors white, gray, and black.

A device'according to this invention operatesresponsive to the colordifference between one of the frame sides and the contiguous-background.More particularly, the device discriminates the specific pattern to berecognized from other patterns by recognizing the differences or thedistinction which is present between the predetermined colors across theboundary lines between the frame and the contiguous portions of thebackground and further recognizing that the distances between theboundary lines are substantially equal to the predetermined dimension ofthe pattern to be recognized. Accordingly, a device according to thisinvention comprises first means for producing color distinction electricsignals responsive to the color distinction between the colors of theframe and the background and second means responsive to such electricsignals for measuring the spatial distance between the lines acrosswhich the color distinction is present.

According to an aspect of the present invention, the above-mentionedfirst means comprises means for deten-mining the width of a zone servingas a side of the frame or forming the margin surrounding the frame.

On the whole, a postage stamp is provided with a design of at least onecolor printed on a generally white background with a margin of at leastabout 1 mm left around the design. This same procedure applies to apostcard having a governmenvimprinted stamp, an envelope having apostage meter stamp or indicia, or a stamped envelope. Theabove-mentioned one aspect of this invention makes use of the fact thatthe margin is at least about 1 mm wide and the side of the color frameis at least about 0.5 mm thick although the particular measurementsdepend on the design. The first means may include means for producing anelectric signal when a first zone of a first predetermined color and ofat least a first predetermined width is contiguous to a second zone of asecond predetermined color and of at least a second predetermined width.

In an embodiment of the present invention illustrated hereinbelow, theabove-mentioned first means comprises first color signal means, which inturn comprises photoelectric means and a color detector and producesfirst color signals or color logical signals. The photoelectric meanscomprises filters responsive to a set of clearly distinguishable colorsand photoelectric transducers. Preferably, the set of colors is suchthat the rays of the colors, when superimposed, would result in whiterays. The first means further comprises second color signal means havingintegrator means and produces second color signal or color pulse trains.The first means still further comprises distinction signal means havinggate means for producing the distinction signals.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an envelopehaving a postage stamp to be recognized by a device according to thepresent invention;

FIG. 2 is a block diagram of an embodiment of this invention;

FIG. 3 shows the intensities of the respective components of threeprimary colors of the rays reflected from various points on the envelopedepicted in FIG. 1;

FIG. 4 shows, a color solid for explaining a color detector used in thedevice illustrated in FIG. 2;

FIG. 5 isa block diagram ofa portion of the color detector; I

FIG. 6 shows logical electric signals produced by the color detector;

FIG. 7 illustrates the circuit, partly in blocks, of a portion of aframe detector used in the device depicted in FIG. 2;

FIGS. 8 through 10 shows signal wave forms appearing in the framedetector; and

FIG. 11 shows edge pulses derived from the frame detector.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. ll, lettermail and postcards, such as a mailed envelope 20, are fed one by onewith a space (not shown) left between two consecutive pieces of mail insuch a manner that a postage stape 21 attached thereto may be scanned bya white light beam projected thereon from a substantially point source22 in the direction illustrated by arrow 23. The relative speed of scanis, for example, 2.8 m/sec. The postage stamp 21 is provided with apattern 25 having a frame portion 26 of a predetermined pattern colorprinted on a predetermined background color with a margin 27 of about 1mm around the pattern 25. The frame 26 is generally rectangular inoutline and the sides are at least about 0.5 mm thick. The lengthwisedistance D between the lines bounding the frame is of a predetermineddimension, such as, for example, 22.5 mm. The envelope 20 may haveletters 29 printed thereon line with the scan.

Referring to FIGS. 1 through 3, it is assumed that substantial portionsof the rays reflected from the margin 27 and the frame 26 pass throughfilters 31, 32 and 33 of three primary colors, such as red, green, andblue, respectively. The rays reflected from the postage stamp bearingsurface of envelope 20 and the postage stamp 21 are received by threephototubes 36, 37, and 38 through the filters 31, 32, and 33 and anoptical system (not shown) for directing preferably equally dividedportions of the reflected rays to the filters 31, 32, and 33,respectively. The phototubes 36, 37, and 38 produce color analogelectric signals R,,, G,,, and B which are representative of the red,the green, and the blue components of the reflected rays, respectively,and vary as the envelope 20 with the postage stamp 21 is scanned by thewhite light beam. In FIG. 3A, the red analog signal R successivelyassumes a first, minimum level 41 corresponding to the dark current ofthe phototube 36 until the light beam reaches the edge of the envelope20, a second level 42 corresponding to the red component of the raysreflected from the face of the envelope 20, a third, maximum level 43corresponding to the rays reflected from the white margin 7 27, a fourthlevel 44 substantially equal to the first level corresponding to therays reflected from the blue frame 26, a fifth, varying level 45responsive to the rays reflected from the inner portion of the pattern25, again the fourth, the third, and the second levels 44, 43, and 42, asixth, varying level 46 responsive to the rays reflected from the areabearing the letters 29, and again the second level 42 and the firstlevel. In FIG. 3B, the green analog signal G undergoes a change similarto the red signal R As shown in FIG. 3C, the blue analog signal Bassumes a level 48 substantially equal to the maximum level 43 when thelight beam relatively scans the blue frame 26. 7

Referring to FIGS. 1 through 6, the color analog signals R G and B, aredelivered to a color detector 49 which may be that disclosed in JapanesePatent Application No. Syo 45-37245 filed Apr. 30, 1970. According tothe application, it is possible as shown in FIG. 4, to represent a givencolor by a point included in a unit color solid in a space having a setof coordinate axes representative of primary colors. The coordinateorigin 0 and the opposing vertex (1, 1, 1) of the unit solid representblack and white, respectively. The diagonal passing through the originand the opposing vertex (1, l, l) is the axis of luminosity, while thesaturation varies in the plane perpendicular to this diagonal. The colordetector 49 recognizes as blue the colors represented by the pointswithin a solid figure 50, that is, by the following inequalities:

where R, G, and B represent normalized red, green, and blue componentsof the color in question and r, g, and b represent the respective red,green, and blue intercepts given by the surfaces of the solid figure 50and consequently determine the allowance for the blue colors. Asdepicted in FIG. 2, the color detector 49 may include three normalizingunits 51, 52, and 53. The red-signal normalizing unit 51 comprises apair of d.c. amplifiers (not shown) for producing a pair of normalizedred analog electric signals R and R. Similarly, the green-signalnormalizing unit 52 produces a pair of normalized green analog signals Gand G, while the bluesignal normalizing unit 53, a pair of normalizedblue analog signals B and B. The color detector 49 may further include acolor discriminator 55 for white and three additional colordiscriminators 56, 57, and 58 for the respective ones of the primarycolors. As exemplified in FIG. 5, the blue discriminator 58 comprises aplurality of adder/comparators 61, 62, 63, and 64. Supplied with thesignals B, R, and b, the first adder/comparator 63 derives the algebraicsum of the input signals and produces a first logical electric signalwhich become logical 0 and 1 according as the algebraic sum is positiveand negative, respectively. The other adder/comparators 62 through 64likewise produce similar logical electric signals, respectively. Thelogical signals are delivered to a four-input NAND circuit 65, with thelogical signals produced by the third and the fourth adder/comparator 63and 64 being inverted by inverter circuits 661 and 662, respectively.The allowance electric signals r, g, and b are produced by adjustablepotentiometers 67r, 67g, and 67b, respectively, symbolically depicted inFIG. 5. Although the same symbols R, G, B, r, g, and b are used, it isbelieved that no confusion will arise between the geometrical orphysical quantities and the analog electric signals representativethereof. It is now understood that the input logical signals of thefour-input NAND circuit 65 is of logical 1 when the geometricalquantities R, G, B, r, g, and b satisfies the inequalities given above.The blue logical electric signals 8,, derived from another invertercircuit 68 supplied with the output of the fourinput NAND circuit 65,becomes a logical 1" or 0 in response to the rays reflected from theenvelope 20 and the postage stamp 21 such that a logical 1 appears if ablue color, represented by a point within the solid FIG. 4 is detectedand a logical 0 appears if a blue color is not detected. The red, thegreen, and the blue logical signals R and G and B, are similarly derivedfrom the color discriminators 56, 57, and 58, respectively. The whitecolor discriminator 55 recognizes the color in question to be white whenthe normalized color components R, G, and B are greater than.preselected values w,,, W and W respectively. For simplicity, thepreselected values may be equal to a single value w. In this simplercase, the whitecolor discriminator 55 may comprise threeadder/comparators (not shown) supplied with the sign-inverted normalizedcolor analog signals R, G, and -B, respectively, and with an allowanceelectric signal w in common. The outputs of the adder/comparators aresupplied to a three-input NAND circuit (not shown) and then to aninverter circuit (not shown) to become the white logical signal W whichbecomes logical 1 when the color to be recognized is within a small cubehaving each edge of the length equal to the difference I w and similarlyplaced with respect to the unit color cube with the white vertex (1,1, 1) in common. The white and the blue logical signals W, and B becomelogical 1" as shown in FIGS. 6A and 6B while the white and the blueareas 27 and 26 are relatively scanned by the light beam, respectively.In FIGS. 6A and 6B, logical 1 and 0 are represented by the lower and thehigher levels, respectively, for ease of description of the later stagesof the embodiment of this invention being described.

The three primary colors may be magenta, yellow, and cyan.Alternatively, a pair of complementary colors may be used instead of aset of three primary colors. Contrarily, two sets or more of the primaryand/or complementary colors may be used. In any event, it is preferablethat one of the colors is the color of the substantial portion of therays reflected from the frame 26. When the background color is clearly adistinguishable color other than white, the color components into whichthe reflected rays are separated by the filters, such as 31 and 32, maynot be those which when added, result in white. In the above-referredpatent application, the inequalities for a solid figure similar to FIG.4

are:

lG Bl c,

where symbols are similar to those used in the present application. Asseen from this, it is possible to modify the color detector 49 invarious ways.

Referring to FIGS. 1, 2 and 7 through 11, the color logical electricsignals W R,,, G,,, and B, are delivered to a frame detector 69 fordetecting the color change at the leading and the trailing edges of theframe 26. As shown in FIG. 7, the pertinent portion of the framedetector 69 comprises a white and a blue integrator 70 and 73, eachoutput of which builds up beyond a predetermined level towardssaturation when the input signal assumes a predetermined level for asufficiently long duration of time and rapidly drops as soon as theinput signal assumes another predetermined level. Such an integrator 70or 73 is called herein may comprise a capacitor C which is chargedthrough a resistor R with a large time constant RC while the inputlogical signal is of logical 1 (low level) to keep a transistor TRshunting the capacitor C in the off state and is rapidly dischargedthrough the transistor TR with a very small time constant CR, as soon'as the input signal become logical 0 (high level) to turn the transistorTR into the on state having a saturation resistance R,,,,. The outputintegration signals W, and B, of the integrators 70 and 73 thereforevary in the manner depicted in FIGS. 8A and 88, respectively. Theseoutput signals W, and B, are supplied to a white and a blue slicer 75and 78 which produce trains of color pulses W and Bp shown in FIGS. 9Aand 9B, respectively, when the time constant RC and the slice level foreach color integration signal are selected in compliance with thepredetermined least width for the color zone, such as the margin 27 andthe frame 26. The pulse trains W and Bp are supplied to a white and ablue monostable multivibrator 80 and 83 connected to a leading andtrailing edge AND circuit 85 and 88 for detecting the color change.Responsive to the trailing edge of each pulse of the white pulse train Wthe white multivibrator 80 produces a white gate pulse W shown in FIG.10A of a predetermined width. Responsive to the trailing edge of eachpulse of the blue pulse train Bp, the blue multivibrator 83 produces ablue gate pulse B illustrated in FIG. 10B of predetermined width. Thepredetermined width is a little longer than the buildup time of theoutput signals of the integrators 70 and 73. Opened by the white gatepulse W produced in response to the margin 27 leading the leading edgeof the frame 26, the leading edge AND circuit 85 gates the blue pulse Bpproduced in compliance with the side of the frame 26 contiguous to theleading margin 27, to provide a leading edge pulse L shown in FIG. 11Arepresentative of the color distinction present across the leading edgeof the frame 26. Similarly, the trailing edge AND circuit 88 allows thewhite pulse W for the trailing margin 27 to pass therethrough to becomea blue trailing edge pulse T shown in FIG. 11B representative of thecolor distinction present at the trailing edge of the frame 26.Preferably, the above-mentioned predetermined width should be about ahalf longer than the duration corresponding to the larger of thepredetermined thickness of the side of the frame 26 and thepredetermined width of the margin 27 so as to cover the fluctuation inthe relative speed of scan, the expansion of the postage stamp 21 due tomoisture, the slant positioning of the postage stamp 21, and the like.

Referring to FIGS. 1, 2, and 11, the edge pulse L and T are supplied toa distance detector 89 whose pertinent components are a delay circuit 90for delaying the leading edge pulse L for the time corresponding to thelengthwise distance D between the leading and the trailing edges of theframe 26 to produce a lengthwise delayed leading edge pulse L and a bluelength AND circuit 938]. supplied with the delayed pulse L and the bluetrailing edge pulse T for producing a recognition signal REC through ablue recognition OR gate 9380. The delay circuit 90 may be a shiftregister caused to step by a clock pulse train CL whose repetitionfrequency is determined in consideration of the distance to be detected,the relative speed of scan, the resolution, the stages of the shiftregisters, and others. With a shift register of sixty-four stages andfor the example being described, the repetition frequency of 7.7 kHzprovides a resolution of 0.37 mm with the delayed pulse L taken out fromthe sixtieth stage. For the postage stamps transversely positioned onthe envelope 20, the delay circuit 90 is provided with an intermediateoutput in compliance with the widthwise distance D between the boundinglines of the frame 26 for producing a widthwise delayed leading edgepulse L which is supplied to a blue width AND circuit 933W together withthe blue trailing edge pulse T,, for producing the recognition signalREC through the OR gate 93B0.

While the present invention has thus far been described with particularreference to recognition of the postage stamps having a white backgroundand a frame of a specific dimensions and of the color reflecting bluerays capable of passing through the blue filter 33, it is obvious tothose skilled in the art that the system can be easily adapted to therecognition of color prints provided with a frame at at least onepredetermined pattern color and of predetermined dimensions on abackground having at least one predetermined background color, the colorprints including the aligning marks.

What is claimed is:

l. A device for electrooptically discriminating a specific pattern fromother patterns, said specific pattern including a frame of predeterminedsize and color on a background of another predetermined size and coloron a background of another predetermined color, comprising:

first means for producing color distinction electric signalsrepresentative of the color distinction between said pattern frame andsaid background colors, and

second means responsive to said electric signals for measuring thespatial distance between the locations of the said color distinctions,wherein said first means comprises:

means for scanning said patterns and background to produce colorindicative rays,

photoelectric means, responsive to the rays of a set of predeterminedcolor components incident thereon, for producing color analog electricsignals representative of the intensities of the rays of the respectiveones of said color components, the substantial component of each of saidpattern and said background colors being at least one of said colorcomponents,

a color detector responsive to said color analog signals for producingcolor logical electric signals for the respective ones of said colorcomponents and for a combination of at least two of said colorcomponents, each said color logical signals assuming a predeterminedlevel when the intensity of the rays of the concerned at least one ofsaid color components incident on said photoelectric means is strongerthan the intensity predetermined for each of the concerned ones of saidcolor components, said color detector comprising potentiometer means forproducing allowance electric signals determinative of the intensitiespredetermined for said color components and for said combination of atleast two of said color components, and

means responsive to said color logical signals produced in response tothe rays incident on said photoelectric means from a zone of saidpattern color and a contiguous zone of said background color forproducing said color distinction signals.

2. A device as claimed in claim 1, wherein said color detector furthercomprising:

normalizing circuits responsive to said color analog signals forproducing normalized color analog electric signals, respectively, and

adder/comparator means responsive to said normalized color analogsignals and said allowance signals for producing said color logicalsignals, each assuming said predetermined level when the algebraic sumof the concerned normalized color analog signals and the concernedallowance signal is negative.

3. A device for electrooptically recognizing a pattern including a frameprovided with a zone of a predetermined pattern color and of at least apredetermined frame width on a background provided with a zone of apredetermined background color and of at least a predeterminedbackground width, said background zone being contiguous to said framezone, the bounding lines between the contiguous frame and backgroundzones being spaced apart by a predetermined distance, comprising:

first means for relatively scanning a given pattern provided on a givenbackground with a light beam,

second means responsive to the light beam modified by that portion ofsaid given pattern and background which is colored in each of saidpattern and background colors for producing a first color electricsignals of a duration proportional to the width of each of saidportions, third means responsive to each said first color signals forproducing second color electric signals when the duration of each saidfirst color signal exceeds a predetermined duration,

fourth means responsive to said second color signals for producing colordistinction electric signals representative of the color change when aportion colored in one of said pattern and said background colors andanother portion colored in the other of said pattern and said backgroundcolors are contiguously scanned, and

fifth means responsive to said color distinction signals for measuringthe spatial distance between the bounding lines across which the colorof the contiguous portions vary from said background color to saidpattern color and from said pattern color to said background color.

4. A device for electrooptically detecting a predetermined pattern froma plurality of patterns, said predetermined pattern being positioned ona background of predetermined background color, said predeterminedpattern including a generally rectangular frame area of preselected sizeand color, at least two parallel sides of said frame being of apredetermined width and spaced from one another by a predetermineddistance, said background including a margin zone extending outwardlyfrom each of said at least two parallel sides at least a predeterminedmargin width comprising:

means for scanning said patterns and background to produce rayscharacteristic of the colors in said patterns and background,

means responsive to said rays for producing a first critical boundaryrecognition signal when said rays indicate said background colorextending over said margin width contiguous to said predetermined framecolor extending over said predetermined side width, and a secondcritical boundary recognition signal when said rays indicate saidpredetermined frame color extending over said predetermined side widthcontiguous to said background color extending over said margin width,and means responsive to said critical boundary recognition signals fordetermining the spatial distance between the locations on the scannedbackground and patterns giving rise to said recognition signals.

5. A method for discriminating a predetermined pattern from a pluralityof patterns situated on a background comprising:

a. providing said predetermined pattern with a frame area of preselectedsize and color, said frame including at least two parallel sides ofpredetermined width and spaced a predetermined distance from each other,

b. preselecting the color of said background area, and providing saidbackground area with a margin zone extending outwardly from saidparallel sides a predetermined margin width,

c. scanning the patterns and background to detect the colors therein andthe width of the color areas,

d. detecting the boundary lines between a first color area having apredetermined width and being of a color corresponding to either thepreselected frame color or background color and a second color areahaving a predetermined width and being of a color corresponding toeither the preselected frame color or background color while being of acolor different from the color of said first area, and

e. measuring the distance between said boundary lines.

6. A device for electrooptically discriminating a specific pattern fromother patterns, said specific pattern including a frame of predeterminedsize and color on a background of another predetermined color, com-'prising:

first means for producing color distinction electric signalsrepresentative of the color distinction between said pattern frame andsaid background colors, and I second means responsive to said electricsignals for measuring the spacial distance between the locations of saidcolor distinctions,

said first means comprising:

means for scanning the patterns and background with a light source toproduce color distinctive rays,

first color signal means responsive to the rays of each of the patternand background colors produced in response to the light rays, forproducing first color electric signals representative of the width ofeach color zone scanned,

second color signal means responsive to said first color signals forproducing second color electric signals when each said width is at leasta predetermined width, said second color signal means includingintegrator means responsive to each of said first color signals forproducing an integration electric signal whose amplitude does not growabove a predetermined level when the width of the given zone representedby the supplied first color signal is smaller than a predetermined widthand whose amplitude builds up beyond said predetermined level and thensaturates when the width of the last mentioned given zone is at leastsaid predetermined width, the amplitude of said integration signalrapidly falling to zero when the supplied first color signal disappears,and slicer means responsive to said integration signal for producingsaid color signals when the amplitude of said integration signal islarger than said predetermined level, and distinction signal meansresponsive to said second color signals for producing said colordistinction signals when zones of predetermined colors are contiguous toeach other. 7. A device for electrooptically discriminating a specificpattern from other patterns, said specific pattern being positioned on abackground of a predetermined background color and having a frame of apredetermined frame color, said frame having an outline including a pairof substantially parallel sides spaced apart by a predetermineddistance, said frame extending inwardly of said outline at least apredetermined frame width from each of said sides, said backgroundhaving a pair of margin zones extending outwardly of said outline atleast a predetermined margin width from said sides, respectively,comprising:

scanning means for relatively scanning said patterns and backgroundsubstantially perpendicular to said sides at a predetermined rate toproduce rays characteristic of the colors in said patterns andbackground and of the widths of said frame and said margin zones, firstmeans responsive to said rays for producing a first and a second colordistinction signal when said scanning means relatively scans a firstzone of said predetermined background color having at least a secondmeans responsive to said first and second color distinctive electricsignals for producing a recognition signal discriminative of saidspecific pattern when said first means produces said first and secondcolor distinctive electric signals with an interval corresponding tosaid distance.

Column 1, line Colurnu 2, line 2' Column 5, lines 32 and 33 Columh 6,line 33 line 40 line 5 6 (SEAL) Attest:

Attesti ng Officer Patent No. 3 745 527 MCCOY M. GIBSON, JR.

' UNITED STATES PATENT OFFICE Y CERTIFICATE OF CORRECTION Dated July 10,1973 Inventor(s) Shoichiro YOSHIMURA et a1 It is certified that errorappears in theabove-identified patent and that said Letters Patent arehereby corrected as shown below:

Delete "is called" and substitute as called Delete "become" andsubstitute becomes Signed arid sealed this 20th day of. August 197 c.MARSHALL DANN Commissioner of Patents FORM PO-105O (10-69) uscoMM-Dc60376-P69 U.S. GOVERNMENT PRINTING OFFICE t 1,! O 3G$-3l|,

1. A device for electrooptically discriminating a specific pattern fromother patterns, said specific pattern including a frame of predeterminedsize and color on a background of another predetermined size and coloron a background of another predetermined color, comprising: first meansfor producing color distinction electric signals representative of thecolor distinction between said pattern frame and said background colors,and second means responsive to said electric signals for measuring thespatial distance between the locations of the said color distinctions,wherein said first means comprises: means for scanning said patterns andbackground to produce color indicative rays, photoelectric means,responsive to the rays of a set of predetermined color componentsincident thereon, for producing color analog electric signalsrepresentative of the intensities of the rays of the respective ones ofsaid color components, the substantial component of each of said patternand said background colors being at least one of said color components,a color detector responsive to said color analog signals for producingcolor logical electric signals for the respective ones of said colorcomponents and for a combination of at least two of said colorcomponents, each said color logical signals assuming a predeterminedlevel when the intensity of the rays of the concerned at least one ofsaid color components incident on said photoelectric means is strongerthan the intensity predetermined for each of the concerned ones of saidcolor components, said color detector comprising potentiometer means forproducing allowance electric signals determinative of the intensitiespredetermined for said color components and for said combination of atleast two of said color components, and means responsive to said colorlogical signals produced in response to the rays incident on saidphotoelectric means from a zone of said pattern color and a contiguouszone of said background color for producing said color distinctionsignals.
 2. A device as claimed in claim 1, wherein said color detectorfurther comprising: normalizing circuits responsive to said color analogsignals for producing normalized color analog electric signals,respectively, and adder/comparator means responsive to said normalizedcolor analog signals and said allowance signals for producing said colorlogical signals, each assuming said predetermined level when thealgebraic sum of the concerned normalized color analog signals and theconcerned allowance signal is negative.
 3. A device for electroopticallyrecognizing a pattern including a frame provided with a zone of apredetermined pattern color and of at least a predetermined frame widthon a background provided with a zone of a predetermined background colorand of at least a predetermined background width, said background zonebeing contiguous to said frame zone, the bounding lines between thecontiguous frame and background zones being spaced apart by apredetermined distance, comprising: first means for relatively scanninga given pattern provided on a given background with a light beam, secondmeans responsive to the light beam modified by that portion of saidgiven pattern and background which is colored in each of said patternand background colors for producing a first color electric signals of aduration proportional to the width of each of said portions, third meansresponsive to each said first color signals for producing second colorelectric signals when the duration of each said first color signalexceeds a predetermined duration, fourth means responsive to said secondcolor signals for producing color distinction electric signalsrepresentative of the color change when a portion colored in one of saidpattern and said background colors and another portion colored in theother of said pattern and said background colors are contiguouslyscanned, and fifth means responsive to said color distinction signalsfor measuring the spatial distance between the bounding lines acrosswhich the color of the contiguous portions vary from said backgroundcolor to said pattern color and from said pattern color to saidbackground color.
 4. A device for electrooptically detecting apredetermined pattern from a plurality of patterns, said predeterminedpattern being positioned on a background of predetermined backgroundcolor, said predetermined pattern including a generally rectangularframe area of preselected size and color, at least two parallel sides ofsaid frame being of a predetermined width and spaced from one another bya predetermined distance, said background including a margin zoneextending outwardly from each of said at least two parallel sides atleast a predetermined margin width comprising: means for scanning saidpatterns and background to produce rays characteristic of the colors insaid patterns and background, means responsive to said rays forproducing a first critical boundary recognition signal when said raysindicate said background color extending over said margin widthcontiguous to said predetermined frame color extending over saidpredetermined side width, and a second critical boundary recognitionsignal when said rays indicate said predetermined frame color extendingover said predetermined side width contiguous to said background colorextending over said margin width, and means responsive to said criticalboundary recognition signals for determining the spatial distancebetween the locations on the scanned background and patterns giving riseto said recognition signals.
 5. A method for discriminating apredetermined pattern from a plurality of patterns situated on abackground comprising: a. providing said predetermined pattern with aframe area of preselected size and color, said frame including at leasttwo parallel sides of predetermined width and spaced a predetermineddistance from each other, b. preselecting the color of said backgroundarea, and providing said background area with a margin zone extendingoutwardly from said parallel sides a predetermined margin width, c.scanning the patterns and background to detect the colors therein andthe width of the color areas, d. detecting the boundary lines between afirst color area having a predetermined width and being of a colorcorresponding to either the preselected frame color or background colorand a second color area having a predetermined width and being of acolor corresponding to either the preselected frame color or backgroundcolor while being of a color different from the color of said firstarea, and e. measuring the distance between said boundary lines.
 6. Adevice for electrooptically discriminating a specific pattern from otherpatterns, said specific pattern including a frame of predetermined sizeand color on a background of another predetermined color, comprising:first means for producing color distinction electric signalsrepresentative of the color distinction between said pattern frame andsaid background colors, and second means responsive to said electricsignals for measuring the spacial distance between the locations of saidcolor distinctions, said first means comprising: means for scanning thepatterns and background with a light source to produce color distinctiverays, first color signal means responsive to the rays of each of thepattern and background colors produced in response to the light rays,for producing first color electric signals representative of the widthof each color zone scanned, second color signal means responsive to saidfirst color signals for producing second color electric signals wheneach said width is at least a predetermined width, said second colorsignal means including integrator means responsive to each of said firstcolor signals for producing an integration electric signal whoseamplitude does not grow above a predetermined level when the width ofthe given zone represented by the supplied first color signal is smallerthan a predetermined width and whose amplitude builds up beyond saidpredetermined level and then saturates when the width of the lastmentioned given zone is at least said predetermined width, the amplitudeof said integration signal rapidly falling to zero when the suppliedfirst color signal disappears, and slicer means responsive to saidintegration signal for producing said color signals when the amplitudeof said integration signal is larger than said predetermined level, anddistinction signal means responsive to said second color signals forproducing said color distinction signals when zones of predeterminedcolors are contiguous to each other.
 7. A device for electroopticallydiscriminating a specific pattern from other patterns, said specificpattern being positioned on a background of a predetermined backgroundcolor and having a frame of a predetermined frame color, said framehaving an outline including a pair of substantially parallel sidesspaced apart by a predetermined distance, said frame extending inwardlyof said outline at least a predetermined frame width from each of saidsides, said background having a pair of margin zones extending outwardlyof said outline at least a predetermined margin width from said sides,respectively, comprising: scanning means for relatively scanning saidpatterns and background substantially perpendicular to said sides at apredetermined rate to produce rays characteristic of the colors in saidpatterns and background and of the widths of said frame and said marginzones, first means responsive to said rays for producing a first and asecond color distinction signal when said scanning means relativelyscans a first zone of said predetermined background color having atleast said margin width and then a second zone of said predeterminedframe color having at least said frame width and when said scanningmeans scans a third zone of said frame color having at least said framewidth immediately followed by a fourth zone of said background colorhaving at least said margin width, respectively, and second meansresponsive to said first and second color distinctive electric signalsfor producing a recognition signal discriminative of said specificpattern when said first means produces said first and second colordistinctive electric signals with an interval corresponding to saiddistance.